Electronic and magnetic reconstructions in La_(0.7)Sr_(0.3)MnO_(3)/SrTiO_(3) heterostructures: a case of enhanced interlayer coupling controlled by the interface

摘要

We report on the magnetic coupling of La_(0.7)Sr_(0.3)MnO_(3) layers through SrTiO_(3) spacers in La_(0.7)Sr_(0.3)MnO_(3)/SrTiO_(3) epitaxial heterostructures. Combined aberration-corrected microscopy and electron-energy-loss spectroscopy evidence charge transfer to the empty conduction band of the titanate. Ti d electrons interact via superexchange with Mn, giving rise to a Ti magnetic moment as demonstrated by x-ray magnetic circular dichroism. This induced magnetic moment in the SrTiO_(3) controls the bulk magnetic and transport properties of the superlattices when the titanate layer thickness is below 1 nm.